1. Field of the Invention
The present invention relates to an on-screen display (OSD) apparatus and method, and particularly to an apparatus and method for displaying and controlling a symmetry-type OSD menu in an image display device such as a television.
2. General Background
In an image display device such as a television, parameters of the display such as volume, brightness, contrast, horizontal size, horizontal position, vertical size and vertical position can be adjusted by way of an OSD menu. The OSD menu is displayed on the screen of the device. A user can directly select and adjust a desired item shown on the screen, and visually confirm the adjustment.
FIG. 4 schematically illustrates a typical OSD menu displayed on a screen according to the prior art. The OSD menu has a plurality of symbols arranged in an elliptical ring, the symbols representing various parameters that can be adjusted. If a symbol is shaded, this indicates that the symbol has been selected by a user. A rectangular bar in the middle of the OSD menu represents a level meter of a selected parameter. A colored portion of the rectangular bar represents a current level of the parameter. The right side extremity of the colored portion fluctuates from left to right and back again according to adjustments made to the parameter.
The user can press a level increase button or a level decrease button, and thereby adjust the current level. Simultaneously, the user can view the result of the level adjustment on the level meter.
However, the level meter does not indicate exact adjustment values. It is difficult for the user to know the precise variation made by pressing the increase or decrease button. Additionally, all the optional items are simultaneously displayed on the OSD menu with the same size. The user can be confused, at least momentarily, as to which optional item is currently selected.
What is needed, therefore, is an apparatus and method which can display and control an OSD menu in an image display device, whereby adjustments to a display parameter are accurately shown to a user, and a display parameter currently selected is readily apparent to the user.